<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>

    </title>
    <style>
        /*固定定位*/
        *{
            margin: 0;
            padding: 0;
        }
        .c1{ height:50px ;
            position: fixed;
            right: 0px;
            width: 50px;
            height: 100%;
             background-color: rgba(255, 0, 0,0.5);
           
        }
        .c2{
           width: 100px;
           height:1800px
            ;
            background-color: rgb(10, 25, 228);
       }
    </style>
</head>
<body>
    <div class="c1">126547821</div>
    <div class="c2"></div>
</body>
</html>